Method and apparatus for producing a solution heat treated sheet

ABSTRACT

The present invention comprises a method and apparatus suitable for accomplishing the method that significantly simplifies the process of making a solution heat treated feedstock. The method comprises continuously casing an aluminum alloy to produce a cast feedstock. Any apparatus which accomplishes continuous casting is appropriate for use with the present invention. Once the cast feedstock is formed, it is hot rolled and quenched during hot rolling to form the solution heat treated feedstock. The apparatus which accomplishes the method of the present invention comprises a continuous caster, at least one hot mill stand, and at least one quenching apparatus before or in the at least one hot mill stand.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority under 35 U.S.C. Section119(e) to U.S. Provisional Application Serial No. 60/355,150, filed Feb.8, 2002 entitled “METHOD AND APPARATUS FOR PRODUCING A SOLUTION HEATTREATED SHEET”; U.S. Provisional Application Serial No.60/427,732, filedNov. 19,2002 entitled “METHOD AND APPARATUS FOR PRODUCING A SOLUTIONHEAT TREATED SHEET”; U.S. Provisional Application Serial No.60/436,194,filed Dec. 23,2002 entitled “METHOD AND APPARATUS FOR PRODUCING ASOLUTION HEAT TREATED SHEET”; and U.S. Provisional Application SerialNo.60/385,227, filed May 31,2002, entitled “METHOD OF MANUFACTURINGALUMINUM ALLOY SHEET”; all of which are incorporated herein by referencein their entirety.

FIELD OF THE INVENTION

[0002] This application relates generally to a process for producingaluminum alloy sheet, and, specifically to a process for producing asolution heat treated sheet.

BACKGROUND OF THE INVENTION

[0003] Aluminum sheets are used in many different applications, fromautomobiles to cans. In many of these applications, a thin, yet strong,aluminum sheet is desired. To serve in a wide number of applications, analuminum alloy product should have not only a high tensile and yieldstrength but also high formability to facilitate shaping, drawing,bending and the like, without cracking, tearing, excessive wrinkling orpress loads.

[0004] In the beverage can industry, for example, the aluminum sheet isused as a can body, can end and tab stock. To produce can ends and tabs,the aluminum alloy sheet is first blanked into a circular configurationand then cupped. The side walls are ironed by passing the cup through aseries of dies having diminishing bores. The dies thus produce anironing effect which lengthens the sidewall to produce a can bodythinner in dimension than its bottom. In the manufacture of complete“two-piece” aluminum beverage containers, it has been the practice inthe industry to separately form the bodies, top ends and tabs. Such endsand tabs are then shipped to the filler of the beverage can and appliedonce the containers have been filled. The requirement for can ends andtabs are generally quite different than those for can bodies. Ingeneral, greater strength is required for can ends and tabs, and thatrequirement for greater strength has dictated that such can ends andtabs be fabricated from an aluminum alloy different from that used incan bodies.

[0005] In the automotive industry, there has been increasing emphasis onproducing lower weight automobiles in order, among other things, toconserve energy. Since the body of most automobiles is comprised ofaluminum alloy sheets, reducing the gauge of the sheets will provide areduction in the weight of the automobile. However, in reducing thegauge of the sheet, one cannot sacrifice the strength of the sheet. Toserve in a wide number of automotive applications, an aluminum alloyproduct needs to be formable and strong. In addition, the alloy shouldhave high bending capability without cracking or severe surfaceroughening, since often the structural products are fastened or joinedto each other by hemming or seaming. Thus, an aluminum alloy sheethaving strength and formability characteristics is needed.

[0006] Various aluminum alloys and sheet products have been consideredfor these various applications, including both heat-treatable andnon-heat-treatable alloys. Heat treatable alloys offer an advantage inthat the sheet products formed from these alloys can be produced at alow gauge, yet still meet the strength and formability requirements.Thus, less raw materials are needed to form the sheet.

[0007] Referring to FIG. 6, precipitation hardening of the sheetproducts to realize desired strength and formability requirements isperformed by two different heat treatments, namely solution heattreatment and precipitation hardening. The heat treating process forsolution heat treatment includes the steps of (a) solutionizing heattreatment at a first temperature (T₀) above the solvus temperature (forthe particular alloy composition) and below the solidus and liquidustemperatures (for that alloy composition) and eutectic melting point (toavoid partial melting of the alloy) to dissolve the alloyingconstituent(s) in the aluminum and (b) a rapid quenching to a secondtemperature (T₁) below the solvus to trap the constituent(s) in aluminumsolid solution. In step (a), the alloy is maintained at the firsttemperature for a time sufficient to dissolve at least substantially, ifnot entirely, soluble constituents (such as intermetallic compounds)into solid solution and to form a homogeneous solid solution. Throughsolutionizing at least substantially all (e.g., at least about 80% andmore typically at least about 95%) of the soluble second phase particlesare dissolved into solid solution. When an alloy is in the form of asolid solution, the elements and compounds which form the alloy areabsorbed, one into the other (or are homogeneous), in much the same waythat salt is dissolved in a glass of water. The solution is thenquenched to a lower temperature to create a supersaturated state orcondition (for the form of the constituent in the quenched alloy). Inother words, the form of the constituent in the alloy will have aconcentration in the solid solution that is greater than the equilibriumvalue for the concentration of that form of the constituent at theparticular temperature and alloy composition. In precipitation heattreatment, the alloy is heated to a third temperature (T₂) higher thanthe second temperature and less than the solvus to control the rate thatthe constituent(s) diffuse out of solution and combine to formintermetallic precipitates. These precipitates distort the crystallattice and act as obstacles to dislocation motion, therebystrengthening the material. Over time, these precipitates increase insize from (a) zones to (b) small clusters of aluminum and alloycomponent atoms to (c) fine coherent particles to (d) coarse incoherentparticles. The maximum strengthening occurs while these particles arestill coherent with the aluminum matrix lattice. In either type of heattreatment, once the sheet is quenched the strength of the sheet can beincreased by artificial aging, through additional thermal treatmentssuch as paint bake treatments.

[0008]FIG. 1 shows an equilibrium phase diagram for a binary alloy ofcopper in aluminum. The temperature ranges at which various processsteps such as annealing, precipitation heat treating and solution heattreating performed are shown in FIG. 1. As will be appreciated, thediagram has a solidus line 100 and a liquidus line 104 defining variousphase regions, namely a solid phase region 108 (which includes phases ofAl and the intermetallic compound CuAl₂), a solid phase region Al 112(which includes phases that correspond to substitutional solid solutionsof copper in aluminum), a solid/liquid phase region Al-L 116 (whichincludes phases that correspond to mixtures of the substitutional solidsolution of copper in aluminum and liquid phase aluminum), and a liquidphase region L 120 (which includes phases that correspond to mixtures ofliquid phase copper and aluminum). As will be appreciated, themechanical properties of the alloy are influenced by the character ofthe particles of the transition phases formed in a specific sequenceduring precipitation hardening. In the precipitation hardening process,the upper limit of the solution heat treatment range of temperatures isbelow the eutectic melting point of the copper/aluminum alloy system andsolidus and liquidus lines (for that alloy composition) and the lowerlimit is above the solvus temperature (for that alloy composition). Theeutectic melting point 124 of about 1018° F. is the melting point of aneutectic mixture (where the liquidus and solidus lines intersect) whichis about 5.65 wt. % copper and 94.35 wt. % aluminum. This temperaturerange, for the copper in aluminum alloy system, as shown in FIG. 1, isbetween about 900 and 1018° F. and, more typically, is between 950 and1018° F.

[0009]FIG. 2 shows a time-temperature-property phase diagram for a 7075alloy, a 2017 alloy, a 6061 alloy and 6063 alloy. FIG. 2 shows the timein which an alloy must be cooled and the critical temperature range overwhich the cooling must occur. The alloy should be cooled fast enough sothat the line of cooling does not intercept the “c” or nose portions200, 204, 208, and 212 of the corresponding curve 216,220,224, and 228for that alloy. In other words, in quenching the cooling line for thealloy (time vs temperature) does not intersect (or stays to the left of)the corresponding curve for the alloy. Each curve defines thetemperature/time regime where nucleation and precipitation ofintermetallic precipitates occurs. For instance, the 7075 alloy,according to FIG. 2, would have to be cooled from 750° F. to below 390°F. in less than 10 seconds. On the other hand, the 2017 alloy would haveto be cooled from 920° F. to below 450° F. in less than 100 seconds.Thus, for different alloys, the time in which the metal should be cooledvaries. In addition, for various alloys, the temperature range overwhich the alloy must be cooled also varies.

[0010] An example of the state of the art in producing solution heattreated sheets is described in U.S. Pat. No. 5,772,802 and 6,045,632,incorporated herein by reference. These patents describe a process forproducing a solution heat treated sheet which requires the aluminumalloy to be cast and run through a hot mill. During hot milling, thestrip or sheet is cooled by a combination of water sprays and thermaltransfer to the hot rolls, but the temperature is maintained above thesolvus temperature. Once the cast alloy exits the hot mill as a sheet,the sheet is quenched to below the solvus temperature and cold rolledinto a coil. Following the cold roll, the sheet is annealed at orreheated to a high temperature to accomplish the solution heat treatmentof the sheet. The solution heat treated sheet is then quenched again andcold rolled to its final gauge and aged before use in its finalapplication.

[0011] The problems with the art as it exists now is that the solutionheat treatment phase, accomplished by a high temperature anneal, is anexpensive undertaking, both in operating costs and capital equipmentcosts. As one of skill in the art recognizes, the energy consumed in andoperating costs of reheating the sheet from a temperature below 400° F.to the temperature of 600° F. to 1000° F. are enormous. In addition, thecost of the capital equipment, the furnace, the heating elements, andthe second quench station all add cost to the final product. The hightemperature anneal requires a period of time to reheat the sheet to atleast or above the solidus temperature, the temperature below which thealloy is solid, and recrystallize the sheet, thus increasing theprocessing time for making the sheet. All of these factors add to thecost of the final product. When the final solution heat treated sheetsells for only pennies a pound, every item that adds to or subtractsfrom cost of the final product-even if it only translates into a savingsof a penny a pound - will have a significant effect on the market.

SUMMARY OF THE INVENTION

[0012] The present invention comprises a method and apparatus suitablefor accomplishing the method that significantly simplifies the processof making a solution heat treated sheet. As used herein, “feedstock”refers to an ingot, bar, plate, slab, strip, and/or sheet. The methodcomprises continuously casing an aluminum alloy to produce a cast strip.Any apparatus which accomplishes continuous casting is appropriate foruse with the present invention. Once the cast strip is formed, it is hotrolled and quenched during hot rolling to form the solution heat treatedsheet. As used herein, “quenching” means any process used to lower thetemperature of the cast strip through thermal transfer. In a typicalquench, nucleation and precipitation of intermetallic precipitates is atleast substantially inhibited to provide a supersaturated state orcondition. The term “hot rolling” means any process to reduce thethickness of the strip at a temperature above about 400 degreesFahrenheit. The phrase “during hot rolling” means any process or itemoccurring between point 1, as indicated on FIG. 5, at time 1 and point 2at time 2. With reference to FIG. 5, the phrase “during hot rolling”refers temporally to the time interval beginning when a portion of strip12 contacts the first roller 25 at point p1 (or time t1) and ending whenthe same portion of the strip last contacts the final roller 23 at pointp2 (or time t2) or spatially to the portion of the strip 12 extendingfrom point p1 to point p2.

[0013] Quenching before or during hot rolling can be accomplished in anynumber of ways. Examples include without limitation submersion of thestrip, sprays or mists directed onto the strip, sprays or mists directedonto the rollers of the hot mill stand or other object contacting thesheet, or any combination of the above. In addition to quench bars beingplaced in the hot mill stands or as a substitute for the quench bars, aseparate quenching station can be placed between the hot mill stands.Quenching may also be accomplished by any other means to reduce thetemperature of the cast strip so as to prevent precipitation.

[0014] In one embodiment of the invention, the cast strip is hot rolledand quenched during hot rolling more than once with varying reductionsin temperature and gauge occurring in the various hot rolling/quenchingsteps. The apparatus which accomplishes the method of the presentinvention comprises a continuous caster, at least one hot mill stand,and at least one quenching apparatus before or in the at least one hotmill stand. Although any aluminum alloys can be used with the process,aluminum alloys that react well to a solution heat treatment processare, generally, aluminum alloys from the 2XXX series, 3XXX series, 6XXXseries, and 7XXX series. The 2XXX, 6XXX and 7XXX series are mostcommonly used with solution heat treating processes.

[0015] The advantages of the present invention include less capitalequipment costs and less operating costs since the present inventionproduces a solution heat treated sheet directly from the hot mill stand.Also, less process time is needed to produce a solution heat treatedsheet according to the teachings of the present invention. In addition,the resultant sheet has the same or better characteristics than solutionheat treated sheets produced in conventional processes. Thus, the sheetproduced by the present invention has high formability and strength, asrequired for use in the applications described herein and otherapplications.

[0016] These and other objects, features, and advantages of theinvention will become apparent from the following best mode description,the drawings and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The figures which follow depict a preferred embodiment of theinvention, and may depict various alternative embodiments. The inventionis not limited to the embodiment or embodiments depicted herein sinceeven further various alternative embodiments will be readily apparent tothose skilled in the art. For the ease of the reader, like referencenumerals in various drawing figures refer to identical structuralelements or components.

[0018]FIG. 1 is a phase diagram for a copper in aluminum alloy with thevertical axis being temperature (degrees Celsius) and the horizontalaxis being copper content (weight percent).

[0019]FIG. 2 is a time-temperature-property diagram for various aluminumalloys with the vertical axis being temperature (degrees Celsius) andthe horizontal axis being time (seconds).

[0020]FIG. 3 is a flowchart depicting an embodiment of the presentinvention.

[0021]FIG. 4 depicts a perspective view of an apparatus according to anembodiment of the present invention.

[0022]FIG. 5 depicts the various junctures at which the presentinvention quenches during hot rolling.

[0023]FIG. 6 depicts the relationship between solution heat treatmentand precipitation heat treatment, with the vertical axis beingtemperature and the horizontal axis being time.

DETAILED DESCRIPTION OF THE INVENTION

[0024] At the outset, it should be understood that this inventioncomprises a method and apparatus for producing a solution heat treatedsheet from various aluminum alloys. The description which followsdescribes a preferred embodiment of the invention, and variousalternative embodiments. It should be readily apparent to those skilledin the art, however, that various other alternative embodiments may beaccomplished without departing from the spirit or scope of theinvention.

[0025] There are specific alloy compositions that react well to beingsubjected to a solution heat treatment process. They are, generally,aluminum alloys from the 2XXX series, 3XXX series, 6XXX series, and 7XXXseries. The 2XXX, 6XXX and 7XXX series are most commonly used withsolution heat treating processes. The range of chemical compositions forthe 2XXX, 3XXX, 6XXX and 7XXX series is shown below in Table 1. TABLE 1Table of Chemical Compositions for Heat Treatable Alloys 2XXX Alloy 3XXXAlloy 6XXX Alloy 7XXX Alloy (weight (weight (weight (weight Elementpercent) percent) percent) percent) Silicon about about 0-1.8 about0.15- about 0-0.6 0-1.4 2.0 Iron about about 0-1.0 about 0-1.0 about0-1.5 0-1.5 Copper about about 0-0.9 about 0-1.2 about 0-3.0 0.7 -7.0Manganese about about .05-1.8 about 0-1.2 about 0-1.0 0-1.4 Magnesiumabout about 0-1.5 about 0.2-2.0 about 0-4.0 0-2.5 Zinc about 0 about0-1.0 about 0-2.5 about 3.0-9.0 Zirconium about about 0.05 about 0 about0-0.5 0-0.5 Aluminum Re- Remainder Remainder Remainder (with usualmainder impurities)

[0026] The 2xxx series alloys have copper as the principal alloyingelement. These alloys require solution heat-treatment to obtain optimumproperties; in the heat-treated condition mechanical properties of thesealloys are similar to, and sometimes exceed, those of mild steel. The3xxx series alloys have manganese as the principal alloying elements.These alloys can provide moderate strength and good workability. The6xxx series alloys contain silicon and magnesium in approximateproportions to form magnesium silicide, which makes these alloysheat-treatable. The 7xxx series alloys have zinc as the major alloyingelement, which, when coupled with a smaller percentage of magnesiumresults in a heat-treatable alloy of very high strength.

[0027] Thus, any aluminum alloy with compositions in the rangesdescribed in the above table are suitable for use with the presentinvention. Although it should be noted that aluminum alloys, other thanthose specifically listed above, may also be appropriate for use in thepresent invention.

[0028] Without wishing to be held to any particular theory, it isbelieved that the hardening effect of solution heat treatment isaccomplished by casting the aluminum alloy at a temperature above theeutectic melting point of the aluminum alloy (and above the meltingpoint or liquidus or solidus lines for that alloy composition) todissolve the copper, magnesium, and other alloying elements in thealuminum. The strip output from the caster has a temperature above thesolvus temperature and typically below the eutectic melting point andliquidus and solidus lines. The alloy with the dissolved copper israpidly quenched during hot rolling to trap the dissolved copper in analuminum solid solution in a form that is supersaturated. Some of thecopper and/or other alloying elements may nucleate and formintermetallic precipitates, such as CuAl₂, which will precipitate out ofthe aluminum solid solution. For example, with reference to FIG. 1,corresponding to a copper in aluminum alloy, quenching causes the solidsolution to be in the Al and CuAl₂ phase region 108 of the phasediagram. These precipitates distort the crystal lattice of the aluminummatrix and act as obstacles to dislocation motion, thereby strengtheningthe material. Maximum strengthening occurs while these particles arestill coherent with the aluminum matrix lattice. Thus, in order toproduce a strong, yet formable solution heat treated sheet, one wouldwish to minimize substantially the precipitation of such precipitatesand maintain the alloy elements dissolved in the aluminum matrix.

[0029] With reference to FIGS. 3, 4, and 5, the method and apparatus ofthe present invention begins by melting 50 the chosen alloy in a furnace(not shown) to produce molten metal 60. The molten metal is thendegassed and filtered 70 in a degassing and filtering device (notshown). This step reduces dissolved gases and particulate matter in themolten metal. The molten metal is then continuously cast 80 in acontinuous casting apparatus 10 to form a cast feedstock 90. The castfeedstock employed in the practice of the present invention can beprepared by any of a number of continuous casting techniques well knownto those skilled in the art, including twin belt casters like thosedescribed in U.S. Pat. No. 3,937,270, and the patents referred totherein. In some applications, it may be advantageous to employ themethod and apparatus described in the following U.S. Pat. U.S. Pat. No.5,363,902; 5,515,908; 5,564,491 and 6,102,102. Other casters may also beemployed. For example, drum casters, such as that described in U.S. Pat.No. 5,616,190 or 4,411,707 or block casters, such as those described inU.S. Pat. No. 5,469,912 may be employed to produce a cast feedstock.Each of the aforementioned patents and patent applications are herebyincorporated by reference herein in their entireties. The cast feedstock90 typically has a temperature of from about 700 to about 1100° F. and agauge of from about 0.500 to about 0.850 inches and more typically agauge of from about 0.500 to about 0.800 inches. As will be appreciated,this temperature is generally above the solvus and below the eutecticmelting point and liquidus and solidus lines. Thus, the temperature isabove the lower limit of the solution heat treatment temperature regimeand, sometimes, above the upper temperature limit for the regime.

[0030] From the continuous casting apparatus 10, the cast feedstock 90is hot rolled and quenched 120 during hot rolling in one or more hotmill stands 20 to produce a hot rolled solution heat treated sheet 130.The hot rolling step is performed to reduce the thickness andtemperature of the cast feedstock. Thickness reduction is performed bypassing the feedstock through rollers having a desired interrollerspacing, while temperature reduction is realized by a combination ofheat transfer from the feedstock to the rollers and quenching. Dependingon the desired final thickness of the sheet 130 and/or the temperaturereduction needed to produce the desired feedstock 130 output temperaturefrom the final hot mill stand, the feedstock 90 can be hot rolled andquenched 100 through more than one hot mill stand 21 and 22 to producethe (fully) hot rolled feedstock 130.

[0031] Quenching in the hot mill stand(s) can be accomplished in anynumber of ways such that a reduction in the temperature of the feedstockis accomplished. Examples include without limitation submersion of thefeedstock, sprays or mists directed onto the feedstock, sprays or mistsdirected onto the rollers of the hot mill stand, or any combination ofthe above. FIG. 4 shows quench bars 30 in the hot mill stand 22. Itshould be understood by one of skill in the art that quench bars can beplaced in any or all of the hot mill stands. In addition to the quenchbars or as a substitute for the quench bars, a separate quenchingstation can be placed between the hot mill stands. Spraying or mistingthe hot rollers will cool down the metal rollers 23 that are typicallyused in a hot mill stand. Cooling down the metal rollers will, in turn,allow heat to be removed from the cast feedstock and transferred to therollers. In addition, as the thickness of the feedstock is reduced, itbecomes easier to remove heat from the feedstock since the rollers havemore surface area on which to work. Quenching may also be accomplishedby any other means to reduce the temperature of the cast feedstock so asto inhibit nucleation and precipitation of intermetallic precipitates.

[0032] To realize the desired properties of the solution heat treatedfeedstock 130, the input and output parameters of the final hot rollingstand are carefully controlled. As can be seen from FIGS. 1 and 2, theinput temperature and gauge of the hot rolled feedstock 110 and the timerequired to traverse the temperature range for solution heat treatingare important. Preferably, the input temperature of the hot rolledfeedstock 110 is maintained at or below the upper temperature of thesolution heat treatment range while the output temperature of thesolution heat treated feedstock 130 is maintained at or below the lowertemperature of the solution heat treatment range.

[0033] Quenching the alloy reduces the temperature of the feedstock by arange and over a time sufficient for the resultant feedstock to possessthe properties of a solution heat treated feedstock. Suitable quenchingfluids include water, air, gases such as carbon dioxide or nitrogen,lubricants used to cool the rolling mills, and the like or a combinationof any of the above. The quench requirements for solution heat treatablealloys generally are an input temperature of about 700 to about 800° F.,an input gauge of about 0.090 inches to about 0.180 inches, and aresident time of about 3 to 12 seconds. The quench requirements requiredfor the specific alloys to be solution heat treated (or quenched) in asingle hot mill stand are listed in Tables 2, 3, 4, and 5. As will beappreciated, the quench variables may be performed once in the first,intermediate, or last hot mill stand or gradually among multiple hotmill stands by modifying the speed of the strip through the stands torealize the desired degree of quenching within the desired timeperiod(s). TABLE 2 2xxx Alloy Table for Input Temperature and QuenchVariables 2XXX Alloy Quench Time and Even more Temperature PreferableMore Preferable Preferable Preferred about 10 about 8 seconds about 6seconds Maximum seconds Time Preferred Input-about Input-aboutInput-about Temperature 700-1100° F. 700-1000° F. 700-900° F. RangeOutput-about Output-about Output-about 250-500° F. 250-450° F. 250-400°F. Preferred from about from about 250° from about 300° F. toTemperature 200° F. to F. to about 750° about 650° F. or even Drop about850° F. F. or even more more preferably or even more preferably about600° F. preferably about 550° F. about 500° F. Preferred about 0.90 toabout 0.100 to about 0.110 to 0.120 Hot Mill 0.150 0.130 Exit Gauge(inches)

[0034] TABLE 3 3xxx Alloy Table for Input Temperature and QuenchVariables 3xxx Alloy Quench Time and Even More Temperature PreferableMore Preferable Preferable Preferred about 12 seconds about 10 secondsabout 8 Maximum seconds Time Preferred Input-about Input-aboutInput-about Temperature 700-1100° F. 700-1000° F. 700-900° F. RangeOutput-about Output-about Output-about 250-500° F. 250-450° F. 250-400°F. Preferred from about 200° from about 250° F. from about 300°Temperature F. to about 850° to about 750° F. F. to about 650° Drop F.or even more or even more F. or even more preferably about preferablyabout referably about 500° F. 550° F. 600° F. Preferred about 0.070 toabout 0.075 to about 0.075 to Hot Mill 0.180 0.150 0.140 Exit Gauge(inches)

[0035] TABLE 4 6xxx Alloy Table for Input Temperature and QuenchVariables 6XXX alloy Quench Time and Even more Temperature PreferableMore Preferable Preferable Preferred about 12 seconds about 10 secondsabout 8 seconds Maximum Time Preferred Input-about Input-aboutInput-about Temperature 700-1100° F. 700-1000° F. 700-900° F. RangeOutput-about Output-about Output-about 250-500° F. 250-450° F. 250-400°F. Preferred from about 200° from about 250° from about 300° F.Temperature F. to about 850° F. to about 750° to about 650° F. Drop F.or even more F. or even more or even more preferably about preferablyabout preferably about 500° F. 550° F. 600° F. Preferred about 0.90 toabout 0.100 to about 0.110 to Hot Mill 0.150 0.130 0.120 Exit Gauge(inches)

[0036] TABLE 5 7xxx Alloy Table for Input Temperature and QuenchVariables 7XXX Alloy Quench Time and Even more Temperature PreferableMore Preferable Preferable Preferred about 4 seconds about 3 secondsabout 2 seconds Maximum Time Preferred Input-about Input-aboutInput-about Temperature 700-1100° F. 700-1000° F. 700-900° F. RangeOutput-about Output-about Output-about 250-500° F. 250-450° F. 250-400°F. Preferred from about 200° from about 250° F. from about 300°Temperature F. to about 850° to about 750° F. or F. to about 650° DropF. or even more even more F. or even more preferably about preferablypreferably about 500° F. about 550° F. 600° F. Preferred about 0.090 toabout 0.100 to about 0.120 to Hot Mill 0.180 0.175 0.170 Exit Gauge(inches)

[0037] The resultant quenched feedstock from the hot mill stand is asolution heat treated product which is immediately available for use orstorage. For either purpose, the feedstock will likely be coiled by acoiling apparatus 40 to allow for ease in handling and transport. Theresultant feedstock has been found to have equal or better metallurgicaland formability characteristics as compared to solution heat treatedfeedstocks produced according to the current art. The solution heattreated feedstock can then be artificially aged to produce a desireddegree of nucleation and precipitation of intermetallic precipitates anddesired precipitate size distribution.

[0038] It will be appreciated by those skilled in the art that there canbe expected some small precipitation of intermetallic compounds thatdoes not specifically affect the final properties. Such minorprecipitation has little or no affect on those final properties eitherby reason of the fact that the intermetallic compounds are of a volumeand/or type, which have a negligible effect on the final properties.However, it is believed that the present invention as described hereinsubstantially minimizes or inhibits the number and type of intermetallicprecipitates that are formed in order to produce a formable, yet strongsolution heat treated feedstock.

[0039] As shown in FIG. 4, in one embodiment of the present invention,three hot mill stands 20, 21, and 22 are used. As will be appreciated, acontinuous heater, such as a solenoidal flux heater, can be positionedbetween the caster and first hot mill stand or between stands to providethe desired input temperature into the first hot mill stand. Such aheater is discussed in U.S. Pat. No. 5,985,058; 5,993,573; 5,976,279;and 6,290,785, each of which is incorporated herein by this reference.In stand one 20, the feedstock's gauge or thickness is reduced in arange of 40% to 75% to a thickness range of preferably about 0.187inches to 0.450 inches, more preferably, about 0.200 inches to 0.350inches and even more preferably, about 0.230 inches to 0.270 inches, instand one 20 and the feedstock's temperature is reduced from an inputtemperature of about 900° F. to about 1100° F. to an output temperatureof no more than about 950° F. with the temperature drop being in therange of over 100° F. In stand two 21, the feedstock's gauge is furtherreduced in a range of about 35 to 60% to a thickness range of preferablyabout 0.100 inches to 0.250 inches, more preferably, about 0.110 inchesto 0.200 inches and even more preferably, about 0.120 inches to 0.180inches and the feedstock's temperature is reduced from about 850° F. toabout 950° F. to an output temperature of no more than about 850° F.with the temperature drop being in the range of approximately 100° F.Thus, going into the final hot mill stand 22, the temperature of thefeedstock is at least about 700° F. In the final hot mill stand of thisembodiment, the gauge is again reduced in a range of 40 to 60% to athickness range of preferably less than about 0.150 inches, morepreferably, about 0.125 inches to 0.95 inches and even more preferablyabout 0.060 inches to about 0.075 inches, while the majority of thequenching and, consequently, the temperature drop, for this embodiment,occurs in the last stand. The feedstock is preferably quenched, in thelast hot mill stand, through the use of quench bars 30 which directwater onto the hot mill rollers 23 such that the temperature drops fromat least about 700° F. to no more than about 550° F. and even morepreferably in a range of about 250-500° F. In one embodiment, the exittemperature of the feedstock is in the range of about 250-450° F., andeven more preferably, the exit temperature of the feedstock from thelast hot mill stand is in the range of about 250-400° F. The feedstockpreferably spends no more than about 10 seconds in the last hot millstand and even more preferably no more than about 6 seconds, dependingon the nature of the alloy used in the process and on the speed of thebelt of the apparatus through the hot mill stand, as shown in Table 2.With reference to FIG. 5, the residence time in any hot mill stand ismeasured from the point that a portion of the feedstock first contactsthe stand's rollers to the point that the same feedstock portion lastcontacts the stand's rollers. For the times listed in Table 2, the beltspeed is approximately 25 to 30 feet per minute. As will be appreciatedby one of ordinary skill in the art, the belt speed will necessitateadjustments in the other variables in Table 2 which are important inproducing a solution heat treated feedstock according to the presentinvention. The feedstock then exits from the last hot mill stand at atemperature below 400° F. and is coiled by a coiling apparatus 40 forstorage or transport. The feedstock can also be further processed,depending on the properties specified for the final product.

[0040] In another embodiment, not shown in a figure, two hot mill standsare used. In stand one, the thickness of the cast feedstock is reducedby approximately 65% to a thickness range of preferably about 0.200inches to 0.300 inches, more preferably, about 0.220 inches to 0.280inches and even more preferably, about 0.240 inches to 0.280 inches, andthe feedstock is quenched enough to reduce the temperature of thefeedstock from the exit temperature of the casting apparatus, usually inthe range of from about 900° F. to 1100° F. to a range of approximately700° F. to 900° F. The cast feedstock then proceeds to the second hotmill stand where, as the last hot mill stand of this embodiment, thethickness of the feedstock is reduced by approximately 55% to athickness range of preferably about 0.100 inches to 0.180 inches, morepreferably, about 0.110 inches to 0.160 inches and even more preferably,about 0.115 inches to 0.150 inches, and the majority of the quenchingand the temperature drop occurs. Again, the feedstock has a residencetime in the last hot mill stand of no more than about 10 seconds,dependent on the alloy used, as shown in Table 2.

[0041] As will be appreciated by those skilled in the art, the extent ofthe reductions in thickness effected by the hot rolling and finalrolling operations of the present invention are subject to a widevariation, depending upon the types of alloys employed, their chemistryand the manner in which they are produced. For that reason, thepercentage reduction in thickness of each of the hot rolling and finalrolling operations of the invention is not critical to the practice ofthe invention. In general, good results are obtained when the hotrolling operation effects a cumulative reduction in thickness within therange of about 15 to 99% and the final rolling effects a reductionwithin the range from about 10 to 85%.

[0042] Typically, the present feedstock 150 has a maximum thickness ofabout 0.10 inches; more typically, the maximum thickness is about 0.090inches. The present feedstock 150 has a minimum thickness of about 0.025inches; more typically, the minimum thickness is about 0.030 inches. Itis known to those skilled in the art that this thickness will continueto decrease with time because of continuous down gauging.

[0043] In a preferred configuration of the present invention, themajority of the quenching occurs in the last hot mill stand, whether oneor more hot mill stands are used. Thus, the input requirements to thislast hot mill stand are particularly relevant. Applicants have foundthat the temperature range into the last hot mill stand should be in therange of about 700° F. to 900° F., in order for the solution heattreatment, which primarily occurs in the last hot mill stand, to beeffective. The gauge of the feedstock as it enters the last hot millstand should be in the range of about 0.100 to 0.200 inches.

[0044] It should be recognized by one of ordinary skill in the art,however, the majority of the quenching and temperature drop can occur inany hot mill stand, between hot mill stands, or in front of the firsthot mill stand, with a lower temperature roll following the quench andtemperature drop. With reference to FIG. 5, for example, quenching canbe performed in front of the initial hot mill rollers 25, by thermaltransfer to one or both of the rollers 25, between rollers 25 and 24, bythermal transfer to one or both of the rollers 24, between rollers 24and 23, and/or by thermal transfer to one or both of rollers 23.

[0045] It should be noted that the output from the last hot mill standis a solution heat treated product with a finish gauge that can beimmediately used in the application for which it was produced. Thus, thesolution heat treatment is occurring in the hot mill stands, eliminatingthe need for any further annealing or quenching.

[0046] After the coiling step, the feedstock may be stored until neededfor further processing 140, as described below. Options for furtherprocessing include: 1) aging 160 for a period of time of about 10 to 25hours and a temperature range of about 270° F. to 400° F.; or 2) coilingor aging 160 for a time period of about 6 to 25 hours and a temperaturerange of from about 270° F. to 400° F. with cold rolling 165 followingthe aging to reduce the gauge of the feedstock by about 20% to 70% andform an aluminum alloy sheet. Other types of processing, including butnot limited to the batch stabilization described below or paint baking,may also performed on the solution heat treated feedstock 130, dependingthe application in which the feedstock will be used.

[0047] It is sometimes desirable, after rolling to final gauge, to batchstabilize the cold-rolled feedstock at an elevated temperature,preferably at temperatures within the range of 220-400° F. for about 6to about 20 hours. This batch stabilization precipitates intermetalliccompounds in a strengthening form, and also increases formabilitythrough recovery of the aluminum matrix. More preferably, the feedstockcan be stabilize annealed at a temperature between 300 and 375° F. forbetween 10 and 20 hours. When the feedstock has been quenched during theabove process so as to substantially minimize precipitation of alloyingelements as intermetallic compounds, the cast feedstock has an unusuallyhigh level of solute super saturation. Thus, the stabilizing step causesthe ultimate tensile strength and yield strength to increase along withformability (as measured by percent elongation in a tensile test, forexample).

[0048] Having described the basic concept of the present invention,reference is now made to the following examples provided by way ofillustration only and should not be interpreted to limit the scope orspirit of the present invention.

[0049] Example 1

[0050] An aluminum alloy having a composition of 0.35% Silicon, 0.65%Iron, 0.15% copper, 0.45% Magnesium, 0.52% manganese, and the balancealuminum (with its usual impurities) was cast as a strip having athickness of 0.75 inches using a continuous feedstock caster similar tothat as substantially shown and described in U.S. Pat. No. 5,515,908;6,102,102 and 5,564,491, all of which are hereby incorporated byreference.

[0051] The hot cast strip was then immediately hot rolled to a finishgauge thickness of 0.055 and quenched during hot rolling. The hot rolledstrip was stabilized at 320° F. for 18 hours. The strip, when tested,had an ultimate tensile strength of 41,500 psi, a yield strength of39,000 psi and 9.1% elongation.

[0052] The principles, preferred embodiments and modes of operation ofthe present invention have been described in the foregoingspecification. The invention which is intended to be protected hereinshould not, however, be construed as limited to the particular formsdisclosed, as these are to be regarded as illustrative rather thanrestrictive. Variations and changes may be made by those skilled in theart without departing from the spirit of the present invention.Accordingly, the detailed description of the invention should beconsidered exemplary in nature and not as limiting to the scope andspirit of the invention as set forth in the appended claims.

We claim:
 1. A method for producing a solution heat treated feedstock,comprising the steps of: a) continuously casting an aluminum alloy toform a cast feedstock; b) hot rolling the cast feedstock; c) quenchingthe cast feedstock at least one of before hot rolling and during hotrolling to form the solution heat treated feedstock.
 2. A methodaccording to claim 1, further comprising the step of coiling thesolution heat treated feedstock.
 3. A method according to claim 1,wherein a first portion of the hot rolling step occurs in a first hotmill stand and a second portion in a second hot mill stand and whereinthe cast feedstock is quenched in both the first and second hot millstands.
 4. A method according to claim 3, wherein a third portion of thehot rolling step occurs in a third hot mill stand and wherein the castfeedstock is quenched in the third hot mill stand.
 5. A method accordingto claim 2, further comprising the steps of: annealing the coiledsolution heat treated feedstock; cold rolling the solution heat treatedfeedstock to achieve a final gauge of the solution heat treatedfeedstock; and, stabilizing the cold rolled solution heat treatedfeedstock.
 6. A method according to claim 2, further comprising thesteps of: aging the coiled solution heat treated feedstock; cold rollingthe solution heat treated feedstock to achieve a final gauge of thesolution heat treated feedstock.
 7. A method according to claim 3,wherein the first hot mill stand reduces the temperature of thefeedstock from at least about 900 degrees Fahrenheit to at least about800 degrees Fahrenheit.
 8. A method according to claim 3, wherein thetemperature of the cast feedstock is reduced in the second hot millstand from at least about 800 degrees Fahrenheit to at least about 700degrees Fahrenheit.
 9. A method according to claim 4, wherein thetemperature of the cast feedstock is reduced in the third hot mill standfrom at least about 800 degrees Fahrenheit to no more than about 550degrees Fahrenheit.
 10. A method according to claim 1, wherein thealuminum alloy has a composition comprising: about 0 to 1.4 weightpercent silicon, about 0 to 1.5 weight percent iron, about 0.7 to 7.0weight percent copper, about 0 to 1.4 weight percent manganese, about 0to 2.5 weight percent magnesium, about 0 to 0.5 weight percentzirconium, with the balance being aluminum with usual impurities.
 11. Amethod according to claim 12, wherein an input temperature to the hotrolling step is in the range of 700 degrees Fahrenheit to about 1100degrees Fahrenheit, an input gauge is in the range of about 0.50 toabout 0.80 inches, a residence time in the hot rolling step is no morethan about 10 seconds, an output temperature from the hot rolling stepis in the range of about 250 degrees Fahrenheit to about 500 degreesFahrenheit, and an output gauge is in the range of about 0.060 inches toabout 0.150 inches.
 12. A method according to claim 1, wherein thealuminum alloy has a composition comprising: about 0.15 to 2.0 weightpercent silicon, about 0 to 1.0 weight percent iron, about 0 to 1.2weight percent copper, about 0 to 1.2 weight percent manganese, about0.2 to 2.0 weight percent magnesium, about 0 to 2.5 weight percent zinc,with the balance being aluminum with usual impurities.
 13. A methodaccording to claim 14, wherein an input temperature to the hot rollingstep is in the range of 700 degrees Fahrenheit to about 1100 degreesFahrenheit, an input gauge is in the range of about 0.50 to about 0.80inches, a residence time in the hot rolling step is no more than about10 seconds, an output temperature from the hot rolling step is in therange of about 250 degrees Fahrenheit to about 500 degrees Fahrenheit,and an output gauge is in the range of about 0.060 inches to about 0.150inches.
 14. A method according to claim 1, wherein the aluminum alloyhas a composition comprising: about 0 to 0.6 weight percent silicon,about 0 to 1.5 weight percent iron, about 0 to 3.0 weight percentcopper, about 0 to 1.0 weight percent manganese, about 3.0 to 9.0 weightpercent zinc, about 0 to 4.0 weight percent magnesium, about 0 to 0.5weight percent zirconium, with the balance being aluminum with usualimpurities.
 15. A method according to claim 16, wherein an inputtemperature to the hot rolling step is in the range of 700 degreesFahrenheit to about 1100 degrees Fahrenheit, an input gauge is in therange of about 0.50 to about 0.80 inches, a residence time in the hotrolling step is no more than about 10 seconds, an output temperaturefrom the hot rolling step is in the range of about 250 degreesFahrenheit to about 500 degrees Fahrenheit, and an output gauge is inthe range of about 0.060 inches to about 0.150 inches.
 16. A methodaccording to claim 1, wherein the aluminum alloy is chosen from a groupconsisting of the 2XXX series alloys, the 3XXX series alloys, the 6XXXseries alloys and the 7XXX series alloys.
 17. A method according toclaim 3, wherein a temperature of the cast feedstock before the firsthot mill stand is in a range of about 900 degrees Fahrenheit to about1100 degrees Fahrenheit.
 18. A method according to claim 3, wherein atemperature of the cast feedstock before the second hot mill stand is ina range of about 700 degrees Fahrenheit to about 1000 degreesFahrenheit.
 19. A method according to claim 4, wherein a temperature ofthe cast feedstock before the third hot mill stand is in a range ofabout 700 degrees Fahrenheit to about 900 degrees Fahrenheit.
 20. Amethod according to claim 4, wherein the quenching step in any hot millstand occurs in no more than about 10 seconds.
 21. A method according toclaim 4, wherein the quenching step in any hot mill stand occurs in nomore than about 8 seconds.
 22. A method according to claim 4, whereinthe quenching step in any hot mill stand occurs in no more than about 6seconds.
 23. A method according to claim 1, wherein a gauge of the castfeedstock before the hot rolling step is in a range of about 0.50 inchesto about 0.80 inches.
 24. A method according to claim 3, wherein a gaugeof the cast feedstock before the second hot rolling stand is in a rangeof about 0.187 inches to about 0.300 inches.
 25. A method according toclaim 4, wherein a gauge of the cast feedstock before the third hotrolling stand is in a range of about 0.090 inches to about 0.180 inchesand wherein a gauge of the feedstock after the third hot rolling standis no more than about 0.150 inches.
 26. A method according to claim 4,wherein the hot rolling step effects a cumulative reduction in thicknessof the cast feedstock in all hot mill stands in a range of about 15 toabout 99 percent.
 27. A method for producing a solution heat treatedfeedstock, comprising the steps of: a) melting an aluminum alloy to forma solid solution; b) continuously casting the solution to form a castfeedstock; c) hot rolling the cast feedstock wherein an inputtemperature of the cast feedstock is at least about 700 degreesFahrenheit; and, d) quenching the cast feedstock during hot rolling toform a solution heat treated feedstock, wherein the solution heattreated feedstock has a temperature after quenching of no more than 500degrees Fahrenheit.
 28. A method according to claim 27, furthercomprising the step of coiling the solution heat treated feedstock. 29.A method according to claim 27, wherein a first portion of the hotrolling step occurs in a first hot mill stand and a second portion in asecond hot mill stand and wherein the cast feedstock is quenched in boththe first and second hot mill stands.
 30. A method according to claim29, wherein a third portion of the hot rolling step occurs in a thirdhot mill stand and wherein the cast feedstock is quenched in the thirdhot mill stand.
 31. A method according to claim 29, wherein the firsthot mill stand reduces the temperature of the feedstock from at leastabout 900 degrees Fahrenheit to at least about 800 degrees Fahrenheit.32. A method according to claim 29, wherein the temperature of the castfeedstock is reduced in the second hot mill stand from at least about800 degrees Fahrenheit to at least about 700 degrees Fahrenheit.
 33. Amethod according to claim 30, wherein the temperature of the castfeedstock is reduced in the third hot mill stand from at least about 800degrees Fahrenheit to no more than about 550 degrees Fahrenheit.
 34. Amethod according to claim 27, wherein the aluminum alloy has acomposition comprising: about 0 to 1.4 weight percent silicon, about 0to 1.5 weight percent iron, about 0.7 to 7.0 weight percent copper,about 0 to 1.4 weight percent manganese, about 0 to 2.5 weight percentmagnesium, about 0 to 0.5 weight percent zirconium, with the balancebeing aluminum with usual impurities.
 35. A method according to claim34, wherein an input temperature to the hot rolling step is in the rangeof 700 degrees Fahrenheit to about 1100 degrees Fahrenheit, an inputgauge is in the range of about 0.50 to about 0.80 inches, a residencetime in the hot rolling step is no more than about 10 seconds, an outputtemperature from the hot rolling step is in the range of about 250degrees Fahrenheit to about 500 degrees Fahrenheit, and an output gaugeis in the range of about 0.060 inches to about 0.150 inches.
 36. Amethod according to claim 27, wherein the aluminum alloy has acomposition comprising: about 0.15 to 2.0 weight percent silicon, about0 to 1.0 weight percent iron, about 0 to 1.2 weight percent copper,about 0 to 1.2 weight percent manganese, about 0.2 to 2.0 weight percentmagnesium, about 0 to 2.5 weight percent zinc, with the balance beingaluminum with usual impurities.
 37. A method according to claim 36,wherein an input temperature to the hot rolling step is in the range of700 degrees Fahrenheit to about 1100 degrees Fahrenheit, an input gaugeis in the range of about 0.50 to about 0.80 inches, a residence time inthe hot rolling step is no more than about 10 seconds, an outputtemperature from the hot rolling step is in the range of about 250degrees Fahrenheit to about 500 degrees Fahrenheit, and an output gaugeis in the range of about 0.060 inches to about 0.150 inches.
 38. Amethod according to claim 27, wherein the aluminum alloy has acomposition comprising: about 0 to 0.6 weight percent silicon, about 0to 1.5 weight percent iron, about 0 to 3.0 weight percent copper, about0 to 1.0 weight percent manganese, about 3.0 to 9.0 weight percent zinc,about 0 to 4.0 weight percent magnesium, about 0 to 0.5 weight percentzirconium, with the balance being aluminum with usual impurities.
 39. Amethod according to claim 38, wherein an input temperature to the hotrolling step is in the range of 700 degrees Fahrenheit to about 1100degrees Fahrenheit, an input gauge is in the range of about 0.50 toabout 0.80 inches, a residence time in the hot rolling step is no morethan about 10 seconds, an output temperature from the hot rolling stepis in the range of about 250 degrees Fahrenheit to about 500 degreesFahrenheit, and an output gauge is in the range of about 0.060 inches toabout 0.150 inches.
 40. A method according to claim 27, wherein thealuminum alloy is chosen from a group consisting of the 2XXX seriesalloys, the 3XXX series alloys, the 6XXX series alloys and the 7XXXseries alloys.
 41. A method according to claim 29, wherein a temperatureof the cast feedstock before the first hot mill stand is in a range ofabout 900 degrees Fahrenheit to about 1100 degrees Fahrenheit.
 42. Amethod according to claim 29, wherein a temperature of the castfeedstock before the second hot mill stand is in a range of about 700degrees Fahrenheit to about 1000 degrees Fahrenheit.
 43. A methodaccording to claim 30, wherein a temperature of the cast feedstockbefore the third hot mill stand is in a range of about 700 degreesFahrenheit to about 900 degrees Fahrenheit.
 44. A method according toclaim 30, wherein the quenching step in any hot mill stand occurs in nomore than about 10 seconds.
 45. A method according to claim 30, whereinthe quenching step in any hot mill stand occurs in no more than about 8seconds.
 46. A method according to claim 30, wherein the quenching stepin any hot mill stand occurs in no more than about 6 seconds.
 47. Amethod according to claim 27, wherein a gauge of the cast feedstockbefore the hot rolling step is in a range of about 0.50 inches to about0.80 inches.
 48. A method according to claim 29, wherein a gauge of thecast feedstock before the second hot rolling stand is in a range ofabout 0.187 inches to about 0.300 inches.
 49. A method according toclaim 30, wherein a gauge of the cast feedstock before the third hotrolling stand is in a range of about 0.090 inches to about 0.180 inchesand wherein a gauge of the feedstock after the third hot rolling standis no more than about 0.150 inches.
 50. A method according to claim 30,wherein the hot rolling step effects a cumulative reduction in thicknessof the cast feedstock in all hot mill stands in a range of about 15 toabout 99 percent.
 51. A method of producing a solution heat treatedfeedstock, comprising the steps of: a) melting an aluminum alloy to forma solid solution; b) continuously casting the solution to form a castfeedstock; c) hot rolling the cast feedstock; and, d) quenching the hotrolled feedstock during hot rolling to form a solution heat treatedfeedstock, wherein a temperature of the cast feedstock is reduced in arange of about 500 to 600 degrees Fahrenheit in a time period of no morethan about 10 seconds.
 52. A method according to claim 51, wherein afirst portion of the hot rolling step occurs in a first hot mill standand a second portion in a second hot mill stand and wherein the castfeedstock is quenched in both the first and second hot mill stands. 53.A method according to claim 52, wherein a third portion of the hotrolling step occurs in a third hot mill stand and wherein the castfeedstock is quenched in the third hot mill stand.
 54. A methodaccording to claim 52, wherein the first hot mill stand reduces thetemperature of the feedstock from at least about 900 degrees Fahrenheitto at least about 800 degrees Fahrenheit.
 55. A method according toclaim 52, wherein the temperature of the cast feedstock is reduced inthe second hot mill stand from at least about 850 degrees Fahrenheit toat least about 700 degrees Fahrenheit.
 56. A method according to claim53, wherein the temperature of the cast feedstock is reduced in thethird hot mill stand from at least about 700 degrees Fahrenheit to nomore than about 550 degrees Fahrenheit.
 57. A method according to claim51, wherein the aluminum alloy has a composition comprising: about 0 to1.4 weight percent silicon, about 0 to 1.5 weight percent iron, about0.7 to 7.0 weight percent copper, about 0 to 1.4 weight percentmanganese, about 0 to 2.5 weight percent magnesium, about 0 to 0.5weight percent zirconium, with the balance being aluminum with usualimpurities.
 58. A method according to claim 57, wherein an inputtemperature to the hot rolling step is in the range of 700 degreesFahrenheit to about 1100 degrees Fahrenheit, an input gauge is in therange of about 0.50 to about 0.80 inches, a residence time in the hotrolling step is no more than about 10 seconds, an output temperaturefrom the hot rolling step is in the range of about 250 degreesFahrenheit to about 500 degrees Fahrenheit, and an output gauge is inthe range of about 0.060 inches to about 0.150 inches.
 59. A methodaccording to claim 51, wherein the aluminum alloy has a compositioncomprising: about 0.15 to 2.0 weight percent silicon, about 0 to 1.0weight percent iron, about 0 to 1.2 weight percent copper, about 0 to1.2 weight percent manganese, about 0.2 to 2.0 weight percent magnesium,about 0 to 2.5 weight percent zinc, with the balance being aluminum withusual impurities.
 60. A method according to claim 59, wherein an inputtemperature to the hot rolling step is in the range of 700 degreesFahrenheit to about 1100 degrees Fahrenheit, an input gauge is in therange of about 0.50 to about 0.80 inches, a residence time in the hotrolling step is no more than about 10 seconds, an output temperaturefrom the hot rolling step is in the range of about 250 degreesFahrenheit to about 500 degrees Fahrenheit, and an output gauge is inthe range of about 0.060 inches to about 0.150 inches.
 61. A methodaccording to claim 51, wherein the aluminum alloy has a compositioncomprising: about 0 to 0.6 weight percent silicon, about 0 to 1.5 weightpercent iron, about 0 to 3.0 weight percent copper, about 0 to 1.0weight percent manganese, about 3.0 to 9.0 weight percent zinc, about 0to 4.0 weight percent magnesium, about 0 to 0.5 weight percentzirconium, with the balance being aluminum with usual impurities.
 62. Amethod according to claim 61, wherein an input temperature to the hotrolling step is in the range of 700 degrees Fahrenheit to about 1100degrees Fahrenheit, an input gauge is in the range of about 0.50 toabout 0.80 inches, a residence time in the hot rolling step is no morethan about 10 seconds, an output temperature from the hot rolling stepis in the range of about 250 degrees Fahrenheit to about 500 degreesFahrenheit, and an output gauge is in the range of about 0.060 inches toabout 0.150 inches.
 63. A method according to claim 51, wherein thealuminum alloy is chosen from a group consisting of the 2XXX seriesalloys, the 3XXX series alloys, the 6XXX series alloys and the 7XXXseries alloys.
 64. A method according to claim 52, wherein a temperatureof the cast feedstock before the first hot mill stand is in a range ofabout 900 degrees Fahrenheit to about 1100 degrees Fahrenheit.
 65. Amethod according to claim 52, wherein a temperature of the castfeedstock before the second hot mill stand is in a range of about 700degrees Fahrenheit to about 1000 degrees Fahrenheit.
 66. A methodaccording to claim 52, wherein a temperature of the cast feedstockbefore the third hot mill stand is in a range of about 700 degreesFahrenheit to about 900 degrees Fahrenheit.
 67. A method according toclaim 51, wherein a gauge of the cast feedstock before the hot rollingstep is in a range of about 0.50 inches to about 0.80 inches.
 68. Amethod according to claim 52, wherein a gauge of the cast feedstockbefore the second hot rolling stand is in a range of about 0.187 inchesto about 0.300 inches.
 69. A method according to claim 53, wherein agauge of the cast feedstock before the third hot rolling stand is in arange of about 0.090 inches to about 0.180 inches and wherein a gauge ofthe feedstock after the third hot rolling stand is no more than about0.150 inches.
 70. A method according to claim 53, wherein the hotrolling step effects a cumulative reduction in thickness of the castfeedstock in all hot mill stands in a range of about 15 to about 99percent.
 71. An apparatus for producing a solution heat treatedfeedstock, comprising: a continuous caster operable cast an aluminumalloy to form a cast feedstock; at least one hot mill stand operable toreduce the thickness of said cast feedstock; at least one quenchingapparatus in the at least one hot mill stand, said at least onequenching apparatus being operable to provide a quenching fluid to coolthe cast feedstock before or in the at least one hot mill stand and formthe solution heat treated feedstock.
 72. An apparatus according to claim71, wherein the quenching fluid is selected from a group consisting ofwater, air, gases, lubricants, and a combination of these fluids.
 73. Anapparatus according to claim 71, wherein the aluminum alloy has acomposition comprising: about 0 to 1.4 weight percent silicon, about 0to 1.5 weight percent iron, about 0.7 to 7.0 weight percent copper,about 0 to 1.4 weight percent manganese, about 0 to 2.5 weight percentmagnesium, about 0 to 0.5 weight percent zirconium, with the balancebeing aluminum with usual impurities.
 74. A method according to claim73, wherein an input temperature to the at least one hot rolling standis in the range of 700 degrees Fahrenheit to about 1100 degreesFahrenheit, an input gauge is in the range of about 0.50 to about 0.80inches, a residence time in the at least one hot rolling stand is nomore than about 10 seconds, an output temperature from the at least onehot rolling stand is in the range of about 250 degrees Fahrenheit toabout 500 degrees Fahrenheit, and an output gauge is in the range ofabout 0.060 inches to about 0.150 inches.
 75. A method according toclaim 71, wherein the aluminum alloy has a composition comprising: about0.15 to 2.0 weight percent silicon, about 0 to 1.0 weight percent iron,about 0 to 1.2 weight percent copper, about 0 to 1.2 weight percentmanganese, about 0.2 to 2.0 weight percent magnesium, about 0 to 2.5weight percent zinc, with the balance being aluminum with usualimpurities.
 76. A method according to claim 75, wherein an inputtemperature to the at least one hot rolling stand is in the range of 700degrees Fahrenheit to about 1100 degrees Fahrenheit, an input gauge isin the range of about 0.50 to about 0.80 inches, a residence time in theat least one hot rolling stand is no more than about 10 seconds, anoutput temperature from the at least one hot rolling stand is in therange of about 250 degrees Fahrenheit to about 500 degrees Fahrenheit,and an output gauge is in the range of about 0.060 inches to about 0.150inches.
 77. A method according to claim 71, wherein the aluminum alloyhas a composition comprising: about 0 to 0.6 weight percent silicon,about 0 to 1.5 weight percent iron, about 0 to 3.0 weight percentcopper, about 0 to 1.0 weight percent manganese, about 3.0 to 9.0 weightpercent zinc, about 0 to 4.0 weight percent magnesium, about 0 to 0.5weight percent zirconium, with the balance being aluminum with usualimpurities.
 78. A method according to claim 77, wherein an inputtemperature to the at least one hot rolling stand is in the range of 700degrees Fahrenheit to about 1100 degrees Fahrenheit, an input gauge isin the range of about 0.50 to about 0.80 inches, a residence time in theat least one hot rolling stand is no more than about 10 seconds, anoutput temperature from the at least one hot rolling stand is in therange of about 250 degrees Fahrenheit to about 500 degrees Fahrenheit,and an output gauge is in the range of about 0.060 inches to about 0.150inches.
 79. An apparatus according to claim 71, wherein the aluminumalloy is chosen from a group consisting of the 2XXX series alloys, the3XXX series alloys, the 6XXX series alloys and the 7XXX series alloys.80. An apparatus for producing a solution heat treated feedstock,comprising: continuous casting means for casting an aluminum alloy toform a cast feedstock; hot rolling means to reduce the thickness of saidcast feedstock; quenching means, said at least one quenching meansproviding a quenching fluid to cool the cast feedstock at least one ofbefore and during hot rolling and form the solution heat treatedfeedstock.
 81. An apparatus according to claim 80, wherein the quenchingfluid is selected from a group consisting of water, air, gases,lubricants, and a combination of these fluids.
 82. An apparatusaccording to claim 80, wherein the aluminum alloy has a compositioncomprising: about 0 to 1.4 weight percent silicon, about 0 to 1.5 weightpercent iron, about 0.7 to 7.0 weight percent copper, about 0 to 1.4weight percent manganese, about 0 to 2.5 weight percent magnesium, about0 to 0.5 weight percent zirconium, with the balance being aluminum withusual impurities.
 83. A method according to claim 81, wherein an inputtemperature to the hot rolling means is in the range of 700 degreesFahrenheit to about 1100 degrees Fahrenheit, an input gauge is in therange of about 0.50 to about 0.80 inches, a residence time in the hotrolling means is no more than about 10 seconds, an output temperaturefrom the hot rolling means is in the range of about 250 degreesFahrenheit to about 500 degrees Fahrenheit, and an output gauge is inthe range of about 0.060 inches to about 0.150 inches.
 84. A methodaccording to claim 80, wherein the aluminum alloy has a compositioncomprising: about 0.15 to 2.0 weight percent silicon, about 0 to 1.0weight percent iron, about 0 to 1.2 weight percent copper, about 0 to1.2 weight percent manganese, about 0.2 to 2.0 weight percent magnesium,about 0 to 2.5 weight percent zinc, with the balance being aluminum withusual impurities.
 85. A method according to claim 84, wherein an inputtemperature to the hot rolling means is in the range of 700 degreesFahrenheit to about 1100 degrees Fahrenheit, an input gauge is in therange of about 0.50 to about 0.80 inches, a residence time in the hotrolling means is no more than about 10 seconds, an output temperaturefrom the hot rolling means is in the range of about 250 degreesFahrenheit to about 500 degrees Fahrenheit, and an output gauge is inthe range of about 0.060 inches to about 0.150 inches.
 86. A methodaccording to claim 80, wherein the aluminum alloy has a compositioncomprising: about 0 to 0.6 weight percent silicon, about 0 to 1.5 weightpercent iron, about 0 to 3.0 weight percent copper, about 0 to 1.0weight percent manganese, about 3.0 to 9.0 weight percent zinc, about 0to 4.0 weight percent magnesium, about 0 to 0.5 weight percentzirconium, with the balance being aluminum with usual impurities.
 87. Amethod according to claim 86, wherein an input temperature to the hotrolling means is in the range of 700 degrees Fahrenheit to about 1100degrees Fahrenheit, an input gauge is in the range of about 0.90 toabout 0.180 inches, a residence time in the hot rolling means is no morethan about 10 seconds, an output temperature from the hot rolling meansis in the range of about 250 degrees Fahrenheit to about 500 degreesFahrenheit, and an output gauge is in the range of about 0.060 inches toabout 0.150 inches.
 88. An apparatus according to claim 80, wherein thealuminum alloy is chosen from a group consisting of the 2XXX seriesalloys, the 3XXX series alloys, the 6XXX series alloys and the 7XXXseries alloys.